1. FIELD OF THE INVENTION
This invention relates to steps of passenger conveyors or escalators including moving stairways, moving pathways, etc.
2. DESCRIPTION OF THE PRIOR ART
Passenger conveyors generally referred to as escalators are nowadays indispensable to buildings for business use as service facilities. With the development of a network of subways in large cities and an increase in the number of stations disposed in high buildings, escalators have in recent years been built in an increasingly large number in subway stations and elevated stations, particularly in urban communities of high population density. The escalators installed in subway and elevated stations are under stringent conditions that have not been experienced by escalators before, and various problems have been raised in connection with installation and operation of escalators in an environment which is entirely different from that in which the predecessors have been installed and operated.
Up to the present, escalators have mostly been installed and operated in department stores and other facilities that cater to a large number of customers. As compared with the environment in which the escalators have hitherto been operated, the environment in which the escalators are now finding themselves poses new problems including the need to increase resistance to corrosion that might be caused by invasion of the escalator structure by underground water and the need to increase the surface strength of steps to avoid damage that might be caused by contact thereof with passengers. Thus, it has been desirable to develop steps of passenger conveyors that can cope with these problems arising from the new environmental conditions.
To meet this requirement, a proposal has been made in, for example, U.S. Pat. No. 2,033,308, to provide steps of an escalator by bending steel sheets. Each step is formed of stainless steel of 1-3 mm thick and worked by means of a press to form a plurality of cleats and grooves arranged alternately in parallel relation.
It has been found that this type of steps formed by means of a press raises a problem that should be solved to convey passengers safe and sound. More specifically, in forming about 100 cleats and grooves on a step of 100 mm in width, difficulties are experienced in absorbing cummulative errors and the clearance between the edges of the step and the skirt guard become irregular in size. When the clearance is smaller than is necessary, noise is produced by metal-to-metal contact between the steps and the skirt guard; when the clearance is larger than is necessary, the body of a passenger may accidently be drawn into the clearance.